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authorDavide Caratti <dcaratti@redhat.com>2020-12-03 10:37:52 +0100
committerJakub Kicinski <kuba@kernel.org>2020-12-03 11:13:37 -0800
commit9608fa653059c3f72faab0c148ac8773c46e7314 (patch)
tree6ba66312b3eaa2d0439d397a6527ee5a3daccfe1 /net
parent43c13605bad44b8abbc9776d6e63f62ccb7a47d6 (diff)
downloadlinux-9608fa653059c3f72faab0c148ac8773c46e7314.tar.bz2
net/sched: act_mpls: ensure LSE is pullable before reading it
when 'act_mpls' is used to mangle the LSE, the current value is read from the packet dereferencing 4 bytes at mpls_hdr(): ensure that the label is contained in the skb "linear" area. Found by code inspection. v2: - use MPLS_HLEN instead of sizeof(new_lse), thanks to Jakub Kicinski Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Acked-by: Guillaume Nault <gnault@redhat.com> Link: https://lore.kernel.org/r/3243506cba43d14858f3bd21ee0994160e44d64a.1606987058.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/sched/act_mpls.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/sched/act_mpls.c b/net/sched/act_mpls.c
index 5c7456e5b5cf..d1486ea496a2 100644
--- a/net/sched/act_mpls.c
+++ b/net/sched/act_mpls.c
@@ -105,6 +105,9 @@ static int tcf_mpls_act(struct sk_buff *skb, const struct tc_action *a,
goto drop;
break;
case TCA_MPLS_ACT_MODIFY:
+ if (!pskb_may_pull(skb,
+ skb_network_offset(skb) + MPLS_HLEN))
+ goto drop;
new_lse = tcf_mpls_get_lse(mpls_hdr(skb), p, false);
if (skb_mpls_update_lse(skb, new_lse))
goto drop;